This invention is directed to garments having a strand-reinforced elastomeric adhesive film laminate adjacent one or more openings of the garment.
Personal care garments often include elasticized portions to create a gasket-like fit around certain openings, such as waist openings and leg openings. Multiple elastic strands can be attached to the openings to provide fit and comfort and to prevent leakage. Alternatively, elastic laminates can be used in the manufacture of such garments to avoid complicated elastic attachment steps during the garment manufacturing process.
One type of elastomeric laminate is a stretch-bonded laminate that includes elastic strands produced from an extruder and bonded to a facing sheet or sheets using a hot melt adhesive. Laminates including pre-made elastic strands can be processed online but require an elastic attachment adhesive with high add-on in order to reduce strand slippage. The cost of making stretch-bonded laminates can be relatively high due to the cost of the facing sheet or sheets, plus the cost of the elastic strands, plus the cost of the adhesive.
Another type of elastomeric laminate can be made using a vertical filament laminate-stretch-bonded laminate (VFL-SBL) process. However, the VFL-SBL process must be in off-line operation due to process complexity.
One drawback associated with conventional elastic strands and elastic laminates around garment openings are leakage and fit problems, particularly around leg openings when the garment is loaded. Such problems result from weakening tension or uneven tension distribution of the leg elastics. More specifically, elastic tension is weakened during wearing because of strand relaxation and strand slippage at elevated temperatures. To prevent leakage, tension of the leg elastics can be increased by increasing the number of strands or by using a high denier of strands at a higher stretching ratio. However, an increase in leg elastic tension is likely to cause a “red mark” on a wearer's skin because tension of the garment is actually concentrated on the narrow surface of the strand instead of the whole elastic laminate. Plus, the tension on the conventional elastic laminate can not be transported or distributed uniformly during use especially when legs are moving. Also, current elastic strand-based laminates cannot be die-cut to curve and fit the body exactly. Making curved elastic strand laminates in a high-speed assembly process requires very complex and precise control which is associated with large capital investment.
Elastomeric adhesive compositions are multifunctional in the sense that they function as an elastomer in a nonwoven composite while also serving as a hot melt adhesive for bonding substrates. Elastomeric adhesive compositions in the form of elastomeric adhesive films are currently recognized as suitable for use in the manufacture of personal care articles. More particularly, elastomeric adhesive compositions can be used to bond facing materials, such as spunbond, to one another while simultaneously elasticizing the resulting laminate. The resulting laminate can be used to form an elastomeric portion of an absorbent article, such as a region surrounding a waist opening and/or a leg opening.
Non-woven elastic adhesive film laminates may require high output of adhesive add-on to achieve a tension target for product application. High add-on of the film laminate may generate a bulky, thick feel and appearance, and high cost. Furthermore, the high adhesive output requirement for the film formation would make on-line processing even more difficult due to the limitation of hot melt equipment output capacity. Also, such film lamination processes are relatively complex and need more precise control than strand lamination since a film edge thinning effect may cause the film to break during stretching.
Some elastomeric adhesive compositions lose their adhesiveness when the compositions are stretched and then bonded between two nonwoven substrates. The elasticity of these elastomeric adhesive compositions (in terms of tension decay) is negatively affected when laminates including the compositions are aged at elevated temperatures, for example around 130 degrees Fahrenheit, which is commonly experienced under hot boxcar storage conditions. It appears that the poor tension and adhesion of such elastomeric adhesive compositions results from the chosen base polymer, tackifier, and plasticizer chemistries as well as the unbalanced ratio of polymer to low molecular weight species in the formulation.
There is a need or desire for an elastomeric laminate that can be used to create elasticized portions of a personal care garment, wherein the laminate does not display high tension decay or delamination. There is a further need or desire for a personal care garment including elasticized portions that possess a soft feel and comfortable fit, while providing adjustable tension to minimize leakage.